Java Coding Problems

176. Implementing the Command pattern

In a nutshell, the Command pattern is used in scenarios where a command is wrapped in an object. This object can be passed around without being aware of the command itself or the receiver of the command.

A classic implementation of this pattern consists of several classes. In our scenario, we have the following:

• The Command interface is responsible for executing a certain action (in this case, the possible actions are move, copy, and delete). The concrete implementations of this interface are CopyCommand, MoveCommand, and DeleteCommand.
• The IODevice interface defines the supported actions (move(), copy(), and delete()). The HardDisk class is a concrete implementation of IODevice and represents the